So says a source close to the star (via TMZ) amid, ahem, growing speculation that a close-up photo of a mystery male's private parts supposedly found on Mila Kunis' hacked cell phone is of him.

According to the insider, Justin never sent his "Friends With Benefits" co-star (or anyone else) an intimate pic. As for the pair of snaps rumored to show JT reclining on a bed and jokingly sporting pink panties on his head? Those have yet to surface online.

Either way, we're guessing the hacking was a big topic of discussion when Justin met up with Scarlett Johansson at New York hot spot 1Oak in the early hours of Thursday morning, not long after very personal self-portraits of her boobs and butt popped up everywhere.

"They were dancing and talking to each other all night like old friends," a spy tells Life & Style. "People were surprised that she showed up with him, but they both seemed happy to see each other."

The New York Post says JT and ScarJo partied with everyone from Bradley Cooper to rocker Lars Ulrich before calling it a night shortly before dawn.

But Jessica Biel, who recently reconciled with Timberlake, doesn't seem to have anything to worry about from his "What Goes Around" video co-star (watch the vid here).

"You can tell [Justin and Scarlett] are great friends and had a blast together," says the L&S source. "Scarlett seemed really into him, but he didn't seem interested because of Jessica. It was like he just considers it a friendship."

Johansson, meanwhile, is working with the FBI to track down the nekkis pic perpetrator, and her lawyer has been busily trying to rid the Internet of her shapely lady bits.

In a cease-and-desist letter sent to websites featuring the stolen images, the legal pit bull warns, "The highly personal and private photographs at issue capture our client self-posing in her own home in a state of undress and/or topless. ... If you fail to comply, you will be acting at your own peril."